Dimming Method Research Articles

Research on adaptive dimming management methods for intelligent lighting systems in port traffic based on ocean weather perception

In challenging visibility conditions, the reliability of existing port lighting systems is significantly affected by abrupt changes in environmental factors (primarily stemming from ocean weather). This study proposes a cloud-edge collaborative dimming model that integrates a combined filter, enabling dynamic adaptation to these weather variations to ensure the stability of the lighting system. Additionally, the application of edge computing not only alleviates computational pressure but also facilitates the model’s ability to achieve effective regional adaptive dimming in accordance with environmental regulations. Experimental results indicate that this method is suitable for scenarios with unknown mutations under extreme conditions, providing a more reliable and intelligent solution for port lighting systems within the Internet of Things (IoT) framework.

Validation of Beam Angle Switching Method Using a LED Lumen Maintenance Testing Device

In today’s world, LED predominantly ousted all forms of light sources because of its long lifetime, reliability, very low power consumption, and excellent controllability. That is why, it became a necessity to find proper methods to examine all its characteristics. As directed in several standards, an accelerated life test (ALT) is a good method to predict LED’s lumen depreciation. In correspondence with these standards, to find that persistency of light output from a medium power LED, a prototype is developed, which has predefined data storage capacity with remote monitoring capability, at the Electrical Engineering Department’s Illumination Engineering Laboratory at Jadavpur University to measure the lumen maintenance factor, junction temperature, and ambient humidity in the defined test chamber. Besides, to test the device a particular case study is done to validate beam angle switching, a method for LED dimming. The case study reveals that the dimming method has no effect on the LED’s junction temperature or light output.

63‐4: A New Single X‐Wire Active Matrix mini‐LED backlight with Motion Blur Reduction for LCD TVs

We have developed a high‐image‐quality 85‐inch 4K HDR LCD display with 2,304 dimming zones using single X‐wire AM mini‐LED backlight unit with motion blur and residual image reduction technology. Our latest work includes the proposed new single X‐wire AM driving method, consists of one matrix controller (DCON) and X‐wires of mini‐LED driver ICs (dimmers), which eliminates extra scanning, sensing lines and pixel/source driver IC using adjustable addressing dimming method, the flexible layout makes the display size easier to expand with low cost, and the H‐scan driving method which is designed for reducing motion blur and residual image using a scanning black frame insertion technology to improve display quality. The proposed mini‐LED BLU can save about 9% power consumption compared to conventional one in normal display.

P‐174: The causes and improvement of the waterfall in Mini/MicroLED Displays

The display product using Mini/MicroLED backlight, in the case of using the PWM dimming method, with the OC (open cell, OC) of the 4‐mask process, there will be a significant change in the horizontal light and dark band under the low gray level, which is called the waterfall phenomenon in the industry. In this paper, the causes of the waterfall phenomenon are analyzed and studied, and three methods of improving the waterfall are proposed. Experimental tests were carried out on the module of 34‐inch 1152 partition, and the display effect before and after the improvement was compared, and the effectiveness of the proposed method was verified.

Highly Sensitive SPAD-Based Receiver for Dimming Control in LiFi Networks

Visible light communication (VLC) is an emerging mode of wireless communication that supports both illumination and communication. One essential function of VLC systems is the dimming control, which requires a sensitive receiver for low-light conditions. The use of an array of single-photon avalanche diodes (SPADs) is one promising approach to enhancing receivers’ sensitivity in a VLC system. However, because of the non-linear effects brought on by the SPAD dead time, an increase in the brightness of the light might degrade its performance. In this paper, an adaptive SPAD receiver is proposed for VLC systems to ensure reliable operation under various dimming levels. In the proposed receiver, a variable optical attenuator (VOA) is used to adaptively control the SPAD’s incident photon rate according to the instantaneous received optical power so that SPAD operates in its optimal conditions. The application of the proposed receiver in systems with various modulation schemes is investigated. When binary on–off keying (OOK) modulation is employed due to its good power efficiency, two dimming control methods of the IEEE 802.15.7 standard based on analogue and digital dimming are considered. We also investigate the application of the proposed receiver in the spectral efficient VLC systems with multi-carrier modulation schemes, i.e., direct current (DCO) and asymmetrically clipped optical (ACO) orthogonal frequency division multiplexing (OFDM). Through extensive numerical results, it is demonstrated that the suggested adaptive receiver outperforms the conventional PIN PD and SPAD array receivers in terms of bit error rate (BER) and achievable data rate.

A Novel Single X-Wire AM Mini-LED Backlight Unit with Motion Blur Reduction for High-Image-Quality LCD TVs

We have demonstrated a high-image-quality 85-inch 4 K high-dynamic-range (HDR) LCD display with 2304 dimming zones using a single X-wire AM mini-LED backlight unit (BLU) with motion blur and residual image reduction technology. Our latest work proposed the new single X-wire AM driving method, consisting of one matrix control IC/dimming controller (DCON) and X-wires of mini-LED driver ICs (dimmers), which eliminates extra scanning, sensing lines and pixel/source driver IC using an adaptive addressing dimming method. Additionally, a single X-wire controlled system can realize a flexible and expandable layout, which can achieve ultra thin and low cost in ultra-high dimming zones and large size display. Furthermore, the horizontal-scan (H-scan) driving method, which reduces motion blur and residual images using a scanning black frame insertion (BFI) technology, is utilized. The proposed mini-LED BLU can save about 9% power consumption compared to the conventional one in normal displays.

P‐10.12: The causes and improvement of the waterfall in Mini/MicroLED Displays

The display product using Mini/MicroLED backlight, in the case of using the PWM dimming method, with the OC (open cell, OC) of the 4-mask process, there will be a significant change in the horizontal light and dark band under the low gray level, which is called the waterfall phenomenon in the industry. In this paper, the causes of the waterfall phenomenon are analyzed and studied, and three methods of improving the waterfall are proposed. Experimental tests were carried out on the module of 34-inch 1152 partition, and the display effect before and after the improvement was compared, and the effectiveness of the proposed method was verified.

An Energy-Saving Road-Lighting Control System Based on Improved YOLOv5s

Road lighting is one of the largest consumers of electric energy in cities. Research into energy-saving street lighting is of great significance to city sustainable development and economies, especially given that many countries are now in a period of energy shortage. The control system is critical for energy-saving street lighting, due to its capability to directly change output power. Here, we propose a control system with high intelligence and efficiency, by incorporating improved YOLOv5s with terminal embedded devices and designing a new dimming method. The improved YOLOv5s has more balanced performance in both detection accuracy and detection speed compared to other state-of-the-art detection models, and achieved the highest cognition recall of 67.94%, precision of 81.28%, 74.53%AP50, and frames per second (FPS) of 59 in the DAIR-V2X dataset. The proposed method achieves highly complete and intelligent dimming control based on the prediction labels of the improved YOLOv5s, and a high energy-saving efficiency was achieved during a two week-long lighting experiment. Furthermore, this system can also contribute to the construction of the Internet of Things, smart cities, and urban security. The proposed control system here offered a novel, high-performance, adaptable, and economical solution to road lighting.

Deep Controllable Backlight Dimming for HDR Displays

High dynamic range (HDR) displays with dual-panels are one type of displays that can provide HDR content. These are composed of a white backlight panel and a colour LCD panel. Local dimming algorithms are used to control the backlight panel in order to reproduce content with high dynamic range and contrast at a high fidelity. However, existing local dimming algorithms usually process low dynamic range (LDR) images, which are not suitable for processing HDR images. In addition, these methods use hand-crafted features to estimate the backlight values, which may not be suitable for many kind of images. In this work, a novel deep learning based local dimming method is proposed for rendering HDR images on dual-panel HDR displays. The method uses a Convolutional Neural Network (CNN) to directly predict backlight values, using as input the HDR image that is to be displayed. The model is designed and trained via a controllable power parameter that allows a user to trade off between power and quality. The proposed method is evaluated against seven other methods on a test set of 105 HDR images, using a variety of quantitative quality metrics. Results demonstrate improved display quality and better power consumption when using the proposed method compared to the best alternatives.

Assessing the electricity energy efficiency of university campus exterior lighting system and proposing energy-saving strategies for carbon emission reduction.

This paper presents efficiencies research and energy-saving strategies for carbon emission reduction of the exterior lighting system of Avşar Campus of Kahramanmaraş Sütçü İmam University, Turkey. Once the campus’s average energy consumption for the previous five years was calculated, it was found to be 18,802 Megawatt hour/year (MWh/year), with 6,203 carbon dioxide (CO2) tons/year emissions. Also, the annual electrical energy consumption for exterior lighting was calculated as 670,395 MWh/year, with annual emissions of 221,170 CO2 tons/year. Inefficient lamp choices in exterior lighting systems and longer than necessary operating times have been identified as the causes of these high values. That’s because High-Pressure Sodium (HPS) lamps with an installed power of 109,050 Kilowatt (kW), which have a low efficiency but a high energy consumption, provide for 70% of exterior lighting. Thus, seven unique energy-saving strategies have been designed with the aim of decreasing total energy consumption and achieving more cost savings as well as less harmful emissions released into the atmosphere. All of the strategies were designed under the following three headings: dimming method, optimization of lamps’ operation times, and retrofitting lamps with new and technological ones. The study’s novelty lies in the creation of seven unique energy-saving strategies for the first time in light of the three headings highlighted, as well as their adjustment to a sophisticated campus with such high energy consumption. Once all of the proposed strategies are compared to the current system, it has been discovered that strategy-7 saves 81.656% energy consumption (547,418 MWh/year), 180,599 CO2 tons/year saving, and € 49,268 (€/year) cost-saving. Such a low energy consumption is vital for a rapidly growing and expanding campus in terms of carbon emissions, cost savings, and environmental quality.

Dimming Control Scheme of Visible Light Communication Based on Joint Multilevel Time-Shifted Coding

Dimming control is an essential objection in the signal designing of visible light communication (VLC), which requires improving the communication performance of the system as much as possible while considering the illumination quality. Here, we studied the problem of high-efficiency transmission in an indoor VLC multi-core light-emitting diode (LED) communication model while considering dimming constraints, and propose a dimming method based on joint multilevel multi-LED time-shifted coding (ML-MTSC). The scheme utilizes the code structure of time-shifted space–time codes to encode and uses pulse amplitude modulation (PAM) to expand it to achieve the dimming control function in the proposed scenario. Simulation results show that the ML-MTSC dimming control scheme proposed in this paper has improved spectral efficiency and error performance compared with the traditional scheme.

식물의 최적 광보상점 추적을 위한 시스템 설계 관한 연구

This paper implemented the PWM(Pulse Width Modulation) dimming control method of LED lighting. The PPFD(Photosynthetic Photon Flux Density) value required for plant growth was recognized, the relationship between illuminance and PPFD was verified, and a light output control system using a illuminometer was finally designed. A smart greenhouse basically requires nutrient solution control, shading control, air conditioning control, and CO2 gas control, and there is a limit to natural light in areas with insufficient sunlight or at times. Therefore, an additional light beam is required. Currently, most of the beam light control systems use the on/off control method. However, if you control the light beam, you can control the plant

IDim: Practical Implementation of Index Modulation for LiFi Dimming

This paper introduces a novel dimming method for Light Fidelity (LiFi) based on a time-domain sample index modulation (TIM), called indexed dimming (iDim). The aim is to provide a wide brightness range, while maintaining a high signal-to-noise ratio (SNR) performance and a high transmission rate. Direct current optical orthogonal frequency division multiplexing (DCO-OFDM) is used and novel line codes are presented. The system performance is experimentally validated by an implementation on a NI PXIe-1085 and NI-7966R Field Programmable Gate Array (FPGA). Implementation results show that the proposed iDim jointly offers multiple benefits compared to existing dimming methods such as amplitude modulation (AM) dimming. Specially, the lowest optical power of the iDim method is measured at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$20~\mu \text{W}$ </tex-math></inline-formula> , which is 10 times lower than the measured limit of AM dimming. The iDim system provides a SNR of 22.5 dB for all brightness levels, while the AM-dimming method dramatically reduces its SNR when light is dimmed. The transmission rate of iDim is also higher than DCO-OFDM. This results in up to 40% reduced optical power per bit when compared to sDim, a pulse-width-modulation (PWM)-inspired dimming method. Therefore, iDim is a promising dimming method for applications targeting extremely low illumination levels.

45.3: Invited Paper: Going Towards High‐Resolution, Uniform AMOLED Displays with a High Brightness Range

Going towards high‐resolution, uniform displays with a high‐brightness range requires optimizations on different topics. This work presents an overview on this subject. To achieve a good uniformity, a compensation method is proposed using a 2T1C pixel circuit, compatible with high‐resolution requirements, improving uniformity by a factor 52.5. In order to further increase the achievable resolution, a new technology stack, using a planar and a vertical TFT is introduced. For increasing the brightness range, a global dimming method, compatible with the 2T1C pixel circuit, is demonstrated.

Toward green cartography & visualization: a semantically-enriched method of generating energy-aware color schemes for digital maps

ABSTRACT We introduce a semantically-enriched method of generating color schemes for various types of digital maps that reduces the energy consumption of the display device while preserving the quality of the original design. Energy-aware design intersects two important trends in cartography. First, as more maps are viewed today on mobile, battery life has become a central constraint influencing design. Second, there is increasing need for green computing, which encourages the efficient use of energy to limit environmental impacts. This paper focuses on one important aspect of energy-aware cartography: color design. Existing research on energy-aware color adjustment methods apply broadly to images or websites. However, the colors used in maps have more structured semantic relationships than most documents viewed on mobile devices, and efforts to account for these relationships while reducing energy consumption are limited. To fill this gap, we mathematically formalize energy-aware map-color adjustment as a constrained optimization problem: we define energy consumption as the objective function and model the preservation of semantic relationships as the search constraints. We evaluate our proposed method against a common color dimming method using four maps with different semantic relationships. The evaluation suggests that our proposed method better preserves the original color semantics.

Research and Design Based on Smart Street Lights Network and Adaptive Dimming Method

In order to respond to the call of "smart city" and combine the actual demand of urban road lighting, this paper studies and designs a network based on smart streetlights and adaptive dimming algorithm. In order to improve the efficiency of data transmission in the smart street lamp monitoring network, an unequal clustering topology control algorithm based on band network (UCTC-BN) is proposed to establish a band topology for data Communication. When selecting the cluster head nodes, the algorithm adopts the candidate cluster head mechanism, and the candidate cluster head determines the non-uniform competition radius according to the remaining energy of the nodes and the distance from the sink nodes, thus achieving the goal of balancing the network energy consumption. In view of the low intelligence of street lights dimming and poor energy saving effect, an improved self-adaptive dimming algorithm based on K-means++ and DAG-SVM is studied, the light and traffic volume are clustered and six-classification dimming model is constructed to realize the intelligent dimming of street lights. Experimental results show that the system can efficiently transmit environmental data and comprehensively adjust street lamp lights, effectively reducing street lamp power consumption.

Optimal local dimming based on an improved greedy algorithm

As a new technology appeared in recent years, the local dimming can effectively reduce the power consumption of a display system and improve its display effect. A suitable local dimming algorithm should have efficient performance and can make the displayed images have higher visual quality. However, most of the existing local dimming methods can not have both of the above advantages. In this paper, the local dimming is taken as an optimization problem. On the basis of our previous work which focuses on reducing the image distortion and power consumption, image contrast ratio which is another important factor of visual quality is also considered. To improve the running efficiency of local dimming, the Greedy Algorithm (GRA) which is one of the simplest heuristic algorithms is used to design the local dimming algorithm. In order to improve the global optimization ability of the GRA, an Improved Greedy Algorithm(IGRA) based on the strategies of Taking out-Putting in and variable search step size is proposed. Experienced in four different types of images and compared with five parameter-based algorithms, the IGRA can obtain a higher visual quality under the same or lower power consumption. It is also proved that the IGRA has more powerful search ability and higher running efficiency by the comparisons with the Improved Shuffled Frog Leaping Algorithm (ISFLA) proposed in our previous work, and two recent algorithms including the Modified Genetic Algorithm (MGA) and the Improved Particle Swarm Optimization (IPSO).

Adaptive light: a lighting control method aligned with dark adaptation of human vision

Light exposure before sleep causes a reduction in the quality and duration of sleep. In order to reduce these detrimental effects of light exposure, it is important to dim the light. However, dimming the light often causes inconvenience and can lower the quality of life (QOL). We therefore aimed to develop a lighting control method for use before going to bed, in which the illuminance of lights can be ramped down with less of a subjective feeling of changes in illuminance. We performed seven experiments in a double-blind, randomized crossover design. In each experiment, we compared two lighting conditions. We examined constant illuminance, linear dimming, and three monophasic and three biphasic exponential dimming, to explore the fast and slow increases in visibility that reflect the dark adaptation of cone and rod photoreceptors in the retina, respectively. Finally, we developed a biphasic exponential dimming method termed Adaptive Light 1.0. Adaptive Light 1.0 significantly prevented the misidentification seen in constant light and effectively suppressed perceptions of the illuminance change. This novel lighting method will help to develop new intelligent lighting instruments that reduce the negative effect of light on sleep and also lower energy consumption.

A Stronger Aadaptive Local Dimming Method with Details Preservation

Local dimming technology focuses on improving the contrast ratio of the displayed images for a great visual perception. It consists of backlight extraction and pixel compensation. Considering a single existing backlight extraction algorithm can hardly adapt to images with diverse characteristics and rich details, we propose a stronger adaptive local dimming method with details preservation in this paper. This method, combining the advantages of some existing methods and introducing the combination of the subjective evaluation and the objective evaluation, obtains a stronger adaptation compared with others. Besides, to offset the luminance reduction caused in the backlight extraction process, we improve the bi-histogram equalization algorithm and propose a new pixel compensation method. To preserve image details, the Retinex theory is adopted to separate details. Experimental results demonstrate the effect of the proposed method on contrast ratio improvement and details preservation.

Artificial Intelligent Technique for Power Management Lighting Based on FPGA

The modern technological advances gave rise to new intelligent ways of performance and management in various fields of our lives. The employment of the artificial intelligent techniques proved influential in enhancing the technological developments and in meeting the demands for new, more efficient, more reliable and faster ways of performing activities and tasks. Lighting systems are an important part of human life. For this reason, it is important to reduce and manage energy consumption properly. Light dimming paves the way for massive energy saving in lighting applications. The options include simply reducing the output during the night and achieve maximum saving with variable dimming. Advantage can be taken of off-peak times (no light needed) to reduce energy consumption significantly. Pulse Width Modulation (PWM) technique is used as dimming method. The proposed system offers intelligent management of lighting to reduce power consumption, extend lamp life and reduce maintenance. In this work, we will be using multiple sensors such as light dependent resistor (LDR) and Motion Sensor (PIR) for LED dimming system to achieve intelligent LED lighting system to manage energy consumption. The data collected by sensors is processed by Artificial Neural Network (ANN), which is implemented by using Field Programmable Gate Arrays (FPGAs), Spartan 3A starter kit that controls the light intensity of LED from changing the duty cycle of the PWM signals. FPGA was used to implement the design, because of the re-programmability of the FPGAs, which can support the re-configuration necessary to implement the design.